| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To use encryption keys different in every communication data transmission unit while suppressing the amount of data transmission for the encryption key exchange. <P>SOLUTION: A mobile station device 10 includes a transmission side encryption key producing unit 27 for producing each encryption key about each communication data included in each IP packet based on order relation information relating to a transmission order of each IP packet. A router 40 includes a header restoring unit 41 for estimating the order relation information about each IP packet to be received, and a reception side encryption key producing unit 45 for producing the encryption key about each communication data included in each IP packet based on the order relation information of each IP packet to be estimated by the header restoring unit 41. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
